Hey Guys. Thats what turned me off off the E-street heads originally.(1.25 valve spring diamiter) I called Edelbrock on Friday to inquire and the tech told me That as of April this year they are know putting 1.46 od springs in the E-street heads. They just havn't updated there web site yet. When I ordered the heads I had the guy measure the OD of the valve spring just in case. They are deffinatly 1.46. The Edelrock tech also said they are the same casting as the performer Rpm with different valve train and no cnc port work. So I think with some port work and a valve sping change could be a good set of heads.